Hello mate,I think you're probably better off posting this in the main window cleaning forum and then I'm sure you'll have no end of people who love giving their opinion telling u what to do. Personally, I never respond and use the site to maybe pick up some useful info but as no one else has yet will give u my opinion.
Is £4500 enough for a van and wfp set up? Yes it is. Obviously you're going to have to be realistic in the age of the van u buy and take the risk everyone does with used vehicles but say 2 grand on a van and £1500 will get u a decent wfp set up or less if you're any good at DIY and able to knock up your own kit.
From my own experience I would highly recommend offering add on services - conservatory roofs/gutter clearing/jet washing patios.drives,decking etc and I also do gardening services- clearance & renovation/returfing/grounds maintenance (as opposed to general garden maintenance which doesn't pay as well). I don't really do anything on an hourly rate,instead I go for bigger renovation jobs for fixed price and typically paying £500-£1000 each.
The add ons have proved so successful I'm moving away from window cleaning more and more because I don't have the time for it and I'm studying for a BTEC in garden design and after qualifying next year will give up the windows all together.
However,that's just how things have worked out for me.But in your position starting up on your own is perfectly do-able on your budget.I split up from my thieving business partner this time last year and got going again February time once Xmas was out of the way. Your priorities are a high ranking website on local search terms i.e. 'your area window cleaners'. Speak to Nat at Avondhu Internet Services (he's often on here) who can do u a pay monthly site so u don't have the initial outlay of hundreds of pounds.
Get yourself listed on all the free business directories such as Yell.com ,freeindex, Yelp etc and write good business descriptions on them as search engines also use these sites. If u can ,look into search engine optimisation and using keywords and get an idea of how SEO works - basically improving your ranking on Google. Probably the most important free site is Google itself and register with Google Business and get listed there.
Your ranking will slowly improve and the better optimised your pages the better it will rank but regardless of where u appear in local searches a half decent site is essential and proved to be my best source of work - combined with business directory listings.
One way to leapfrog the rankings is with a Google Adwords campaign (I started with £50/month max budget) and u might appear at top of page 1...or your ad might not appear until bottom of page 3 it varies but worksedfor me.
You'll hear differing opinions on value of flyers but I've always found them an excellent source of business for the outlay - 1000 double sided A5 flyers printed and delivered to u on Ebay = approx £40. I used one side for windows and one for add ons,but don't expect an immediate response.I'm still getting calls from flyers I delivered in May/June!
If interested in add ons some will say you've got to spend thousands on sky vacs and industrial pressure washers - no u haven't. Get what u can afford when u can afford it. I bought a 2500watts jet washer that paid for itself after the 1st job and has earned me a couple of grand on its own since March 2015 (plus sanding/sealing block paving) and nothing but happy customers and recommendations. Just be accurate and honest about what you're offering so yes,a high powered pressure washer worth several grand might be nice,but u don't have to have that to make good money.
If u don't mind ladders get a sturdy set for doing gutters and worry about sky vacs later if u think a good investment.
As for income,once u get established u CAN make reasonable/decent money but u need to be patient and don't expect it to happen overnight. I'm from Kent and for a typical 3 bed semi I charge £15 so only need 10 a day for £150 x5 = £750 week.
But I say 'ONLY need 10 a day' but you've got to build it up to that stage first.
Other costs to consider are Public Liability Insurance (£10-£15 a month),vehicle insurance with business cover,advertising etc.
And if after work experience I'd try a lot nearer to home than 100 miles away.
Hope been of some use,I'll shut up now and very best of luck to u mate.
(and try main chat forum for more opinions and alternative points of view).